Typically, a substrate processing apparatus for processing a wafer for a semiconductor device or a substrate such as a glass substrate or the like used to manufacture a FPD (Flat Panel Display) panel such as a LCD (Liquid Crystal Display) panel, a solar cell and the like includes a processing chamber (hereinafter referred to as a “chamber”) in which a substrate to be processed is provided. Deposits on a chamber inner wall or particles resulting from reaction products generated in a specific process are floating in the chamber. When these floating particles are adhered to a surface of a wafer, a wiring circuit short may occur in a product made from the wafer, such as a semiconductor device, which may result in deterioration of yield of semiconductor devices. To overcome this problem, the particles in the chamber are removed from the chamber while exhausting gas in the chamber by means of an exhaust system of the substrate processing apparatus.
The exhaust system of the substrate processing apparatus includes an exhaust chamber (manifold) communicating with the processing chamber via an exhaust plate, a TMP (Turbo Molecular Pump) which is a high vacuum exhaust pump, and a communication pipe communicating the TMP with the manifold. The TMP includes a shaft disposed along a flow of an exhaust gas and a plurality of rotational blades protruding at a right angle from the shaft and exhausts an intaken gas as the rotational blades rotate around the shaft at a high speed. The exhaust system discharges the particles in the processing chamber along with the gas in the processing chamber by operating the TMP.
However, in some cases, deposits adhered to the rotational blades of the TMP may be peeled off or particles included in the gas intaken by the TMP or residues introduced from the manifold into the TMP via the communication pipe may be bounced by collision with the rotational blades of the TMP. The deposits peeled out of the rotational blades and the particles being bounced by the collision with the rotational blades have high kinetic energy due to the high speed rotation of the rotational blades, thereby allowing the deposits and the particles to be flown backward through the communication pipe into the chamber.
To cope with the above-mentioned backflow of particles, the present inventors have suggested a reflecting device for reflecting particles being bounced from a TMP toward the TMP and a capture mechanism for capturing the particles (e.g., see Japanese Patent Application Publication No. 2007-180467 (JP2007-180467A)). The reflecting device and the capture mechanism disclosed in JP2007-180467A can reflect most of the bounced particles back to the TMP or capture them.
However, the reflecting device disclosed in JP2007-180467A deteriorates exhaust efficiency by decreasing a conductance of an exhaust passage since the reflecting device is arranged to interrupt an exhaust pipe. In addition, although the capture mechanism disclosed in JP2007-180467A is arranged along the inner side of the exhaust pipe, it requires a predetermined thickness to capture particles introduced into the capture mechanism since the introduced particles lose their kinetic energy through repeated collision with components of the capture mechanism. As a result, the capture mechanism is protruded into the exhaust pipe, thereby deteriorating the exhaust efficiency by decreasing the conductance of the exhaust passage. The deterioration of the exhaust efficiency results in increased time taken for vacuum exhaustion of a chamber and low operability of a substrate processing apparatus.
In addition, although JP2007-180467A discloses the capture mechanism formed of a cotton-like material composed of fibers, these fibers are likely to disintegrate from the cotton-like material. In addition, if some of the disintegrated fibers are dropped on the TMP, rotational blades of the TMP are likely to be damaged.